输入三角形。形的三条边a，b，c的值，根据其数值，判断能否构成三角若能则求出三角形的面积

vb作业，谢谢

Private Sub Command1_Click()
Dim a As Double, b As Double, c As Double
a = CDbl(InputBox("请输入第一边的长度"))
b = CDbl(InputBox("请输入第二边的长度"))
c = CDbl(InputBox("请输入第三边的长度"))
If a + b < c Or a + c < b Or b + c < a Then
MsgBox "不能构成三角形"
Exit Sub
End If

MsgBox "三角形的面积是" & Format(area(a, b, c), ".00")
End Sub

Function area(a As Double, b As Double, c As Double)
Dim p As Double
p = (a + b + c) / 2
area = Sqr(p * (p - a) * (p - b) * (p - c))
End Function

Option Explicit

Dim a As Single, b As Single, c As Single, p As Single, S As Single Private Sub Command1_Click() On Error GoTo e a = InputBox("a=") b = InputBox("b=") c = InputBox("c=") p = (a + b + c) / 2 If a < p And b < p And c < p Then S = Sqr(p * (p - a) * (p - b) * (p - c)) MsgBox S Else GoTo e End If Exit Sub e: MsgBox "不能构成三角形" End Sub